George e



(No Model.) v

G. E. WILBUR.

OVEN THERMOMETER.

Patented Feb. 25, 1896.

Wn- JEEEEE ANDREW B GRAHAM PHOTO UTNOYWASMNGTON DC UNITED STATES PATENTOFFICE GEORGE E. \VILBUR, OF TAUNTON, MASSACHUSETTS, ASSIGNOR TO THE\VEIR STOVE COMPANY, OF SAME PLACE.

OVEN-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 555,275, dated February25, 1896.

Application filed October 19,1895. Serial No. 566,201- (No model.)

To all whom, it may concern.-

Be it known that I, GEORGE E. \VILBUR, a citizen of the United States,residing at Taunton, in the county of Bristol and State ofMassachusetts, have invented a new and useful Improvement in OvenThermometers, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, forming apart of this specification, in explaining its nature.

The invention relates to the herein described oven-thermometer and meansfor attaching it to the oven-door or other support.

Figure 1 is a view in front elevation of an oven-door equipped with myinvention. Fig. 2 is aview, enlarged and in plan, of the plate orsupport to which the thermometer is attached. Fig. 3 is a view of rearelevation in said plate and of the parts of the thermometer mountedthereon. Fig. 4: is a view in vertical section upon the dotted line 4. 4of Fig. 1. Fig. 5 is a view in vertical section upon the dotted line 5 5of Fig. 1.

In the drawings, A represents the ovendoor. It has the circular hole a,which is partially covered by the name-plate a upon the outer side ofthe door and bolted to it. This name-plate has a curved recess or hole ain line with the hole a in the oven-door, and which is of a size andshape to receive the dial or indicator plate B of the thermometer orpermit it to be seen and read, the indicatorplate being preferably of acrescent form. This plate is attached to the outer surface, 0, of adish-shaped plate O, forming the casing and support of the thermometer.It has a cavity which opens into the oven and is surrounded by acircular wall 0 and the flange 0 The wall is of a size to fit and enterthe hole a in the oven-door and the flange has ears 0 in which arebolt-holes 0 which receive the bolts 0 that fasten the name-plate to theoven-door, so that the name-plate and the thermometer are secured to theoven-door by the same bolts.

The thermometer comprises a cast-iron ring D of a size slightly smallerthan the wall 0 This ring is not continuous, the end cl being preferablyflattened and made fast to the dishplate by the screw d and the lugs orears (1 while the other end, (7 of the ring is free to move and isconnected with the indicatorhand (1 by a link (1 which is pivoted at dto the free end of the ring and at cl to the indicator-hand, theindicator being pivoted at d to the inner surface, (1 of the fixed end(I of the ring, this inner surface preferably being depressed somewhat,forming a recess or chamber which is protected by the wall d and thesurface d of which is in line with the inner side of the free end of thering. The indicator-hand d is in the main upon the outside of thedish-plate and it extends upon the dial or indicator plate. This resultis reached by forming a hole 0 in the back of the dish-plate and byproviding the hand with the inset-section d at its pivoted end, whichprojects through the hole. The body of the ring is thin and fiat incross-section and it is divided into the parts 6 e e byinwardlyextending sections 6 6 6 which are of the shape of a right angleand between which extend rods or tubes of a metal more expansible thancast-iron, such as brass or a composition thereof. These expansible rodsare lettered e 6 e respectively, and each extends between two ends of asection of the ring, forming an arc, and is held thereto by means ofahole e which does not extend through the angle and against which theend of the rod bottoms, andahole e which does extend through the angleis threaded and receives athreaded adj usting-stud e, which is adaptedto be screwed against the end of the rod which enters said hole and thussecures it in place with any desired stress, bringing the arc of thering across which it extends to any desired tension. It will beunderstood that by adjusting these studs the ring is easily set to ashape necessary to bring the hand at one or the zero side of the dial atnormal temperature; and it will also be understood that upon the heatingof the rods the circle described by the ring is enlarged, therebycausing its free end to draw on the link and move the indicator-handalong the dial.

By holding the thermometer in a dish-plate open to the oven it is madeimmediately sensitive to variations in the heat thereof. The indicatoror dial bears upon its exposed surface the degrees of heat desirable forvarious kinds of cooking. For instance, opposite 200 is Boil; opposite300 Spongecake, roast; opposite 400 Pies, bread.

While I have described the indicator as attached to oven-door and usedin connection with cooking-stoves and ranges, I would not be understoodas limiting the invention to such location or use.

I have described the ring as having three extensible rods, but I do notcommit myself to that number. It will be understood that the cast-ironring is adapted to be enlarged by the extension of the rods under heat,and that as the rods cool it resumes its original size and shape.

Having thus fully described my invention, I claim and desire to secureby Letters Patent of the United States- 1. A heat-indicator comprising acast-iron ring, one end of which is fixed and the other end free, andone or more rods or tubes extensible by heat attached to the ring toextend across an are or arcs thereof and by its or their extensionspread or increase the size of the ring whereby the free end thereof isprovided with movement and an indicatorhand connected with said freeend, substantially as described.

2. In a heat-indicator the cast-iron ring fastened at one end and havingthe other end free provided with the angular sections 6 e e andextensible rods or tubes 2 e e extending across the ring between theangular sections thereof, as and for the purposes described.

3. In a heat-indicator the cast-iron ring one or more tubes or rodsextensible byheat connected with the ring and means for exerting tensionupon the sections of the ring which they connect, as and for thepurposes described.

4. In a heat-indicator the combination of the cast-iron ring one end ofwhich is fixed and the other free, an extensible rod or tube arrangedacross the arc of the ring and bearing at one end against the ring andan adjusting screw or device carried by the ring to bear against theother end of said extensible rod or tube, as and for the purposesdescribed.

5. In a heat-indicator the cast-iron ring having the base cl andindicator-hand pivoted to said base, one or more rods or tubesextensible by heat arranged across an are, or arcs of the ring, and adevice connecting the free end of the ring with the indicator-handwhereby its movement is imparted thereto, substantially as described.

6. In a heat-indicator a plate having upon its outer side acrescent-shaped dial, a hole in said plate through which theindicatorhand extends, a cavity upon the inner side of said plate opento the oven and the heatindicator contained in said cavity comprising acast-iron ring, one end of which is fixed to the plate and the free endof which is connected with the indicator-hand; one or more rodsextensible by heat extending across one or more arcs of the ring, as andfor the purposes described. I

GEORGE E. IVILBUR.

In presence of- NELLIE B. LEONARD, ELISHA T. JACKSON.

